Field-cycling long-lived-state NMR of 15N2 spin pairs
Field-cycling long-lived-state NMR of 15N2 spin pairs
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DOI：
10.1080/00268976.2018.1543906
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发表时间：
2019-04-18
影响因子：
1.7
通讯作者：
Levitt, Malcolm H.
中科院分区：
文献类型：
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作者：
Elliott, Stuart J.;Kaderavek, Pavel;Levitt, Malcolm H.
溶液磁化寿命短，限制了核磁共振波谱和成像应用的范围。长寿命态正在慢慢放松核自旋的组态，已被证明可以缓解这一限制。长寿命态的衰变寿命大大超过了纵向弛豫时间，在某些情况下甚至超过了一个数量级。在这里，我们提供了一个N-15标记的分子体系在溶液中长寿命的实验案例。我们观察到长寿命态的强双指数衰减，慢弛豫分量的寿命超过40分钟，类似于自旋晶格弛豫时间的21倍。利用专用的双场核磁共振谱仪可以在高磁场和低磁场之间快速穿梭样品，并在低磁场下施加共振射频场，从而揭示了长寿命态的寿命。研究了长寿命态的驰豫特性。
A range of nuclear magnetic resonance spectroscopy and imaging applications are limited by the short lifetimes of magnetisation in solution. Long-lived states, which are slowly relaxing configurations of nuclear spins, have been shown to alleviate this limitation. Long-lived states have decay lifetimes significantly exceeding the longitudinal relaxation time , in some cases by an order of magnitude. Here we present an experimental case of a long-lived state for a N-15 labelled molecular system in solution. We observe a strongly biexponential decay for the long-lived state, with the lifetime of the slowly relaxing component exceeding 40 minutes, similar to 21 times longer than the spin-lattice relaxation time . The lifetime of the long-lived state was revealed by using a dedicated two-field NMR spectrometer capable of fast sample shuttling between high and low magnetic fields, and the application of a resonant radiofrequency field at low magnetic field. The relaxation characteristics of the long-lived state are examined.